Geometry
Lateral area
The curved side only, which unrolls into a circular sector.
The Formula
lateral area = pi x r x l
The curved side only, which unrolls into a circular sector.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| A_lateral | Lateral area | square length units | The area of the curved side. |
| r | Radius | same length unit | The radius of the base, which is the arc of the sector. |
| l | Slant height | same length unit | The radius of the unrolled sector. |
What Each Symbol Means
A_lateralsquare length units
Lateral area
The area of the curved side.
rsame length unit
Radius
The radius of the base, which is the arc of the sector.
lsame length unit
Slant height
The radius of the unrolled sector.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate the surface area of a cone page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate The Surface Area Of A Cone, filed under Math. Every number the guide produces comes from substituting into this one line.